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Sunday, May 6, 2012

Earprints Leave Their Mark in Germany

Der Spiegel recently reported that "earprints . . . are as useful to the police as finger prints. A burglar in Germany made the mistake of pressing his ear to front doors to check if anyone was home. The unique prints have allowed the police to pin 96 burglaries on him" [1].

The article makes no mention of the flap over earprints in England [2]. In 1998, a small-time burglar named Mark Dallagher made legal history when he became the first man to be convicted of murder by earprint evidence [3]. A jury found him guilty of murdering 94-year-old Dorothy Woods after Cornelis van der Lugt, a Dutch earprint expert, said he was "absolutely convinced" that Dallagher had made the prints found on the window of Miss Wood's house [3]. Eventually, however, DNA was recovered from the earprints, and it did not match Dallagher's. Following "an appeal, a retrial and a fresh police investigation the Crown said it had 'anxieties' about the case and was offering no evidence against Dallagher'" [3]. Thus, he was acquitted of the murder in 2004 [3].

Despite the bad press the Dallagher case generated, "earprints" are not without value in criminal investigations. Obviously, earmarks vary across individuals. Of course, so do repeated impressions of the same ear, but studies indicate that there is discriminating value in the marks [4-7]. Interestingly, in light of Dallagher, another study suggests that DNA recovered from earmarks can produce false exclusions. When DNA in "60 earprints collected from three healthy adult volunteers under controlled laboratory conditions" was analyzed, "high levels of non-donor alleles [were] observed" [8]. (This is from the abstract of the study. I have not had time to read the body of the paper or check for follow-up work.)

It seems clear, however, that reports like the one in Der Spiegel unconditionally praising the power of "unique prints" cannot be reconciled with the research to date. Fortunately, the German police in the case against the 33-year-old Macedonian linked to some 100 robberies have more to go on than the man's ears. A Hamburg police spokeswoman also referred to fingerprints and DNA [9].